Graphite is one of allotropes of carbon and presents a hexagonal crystal form. Since graphite, although it is a solid substance, is superior in lubricating quality and further has useful properties such as thermal conductivity, heat resistance, chemical resistance, and such, graphite has various uses.
One of methods for producing graphite is to heat carbon sources such as coke or charcoal (generally containing amorphous substances and impurities) up to very high temperatures, 2500-3000 degrees C. for instance so as to graphitize (crystallize and purify) them.
Because graphitization as discussed above requires very high temperatures, there are so many problems difficult to be solved in light of what means for heating should be applied, and heat resistance of structures for supporting the means. External heating means such as a carbon heater cannot realize temperatures over 2500 degrees C. and the heater by itself will, before reaching the temperatures, be thermally damaged. Therefore, generally in the prior art, so-called “Acheson” furnaces or its variations have been used, which applies electric current to carbon sources to execute heating.
The Patent Literatures 1-3 disclose related arts.